fix: allow empty commit when preparing release PR (#733)

When the version in pyproject.toml already matches the requested release
version, sed makes no change and `git commit` fails with "nothing to commit".
Add --allow-empty so the release branch/PR is still created.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: thomasrockhu-codecov

.github/workflows/create_release_pr.yml

@@ -37,7 +37,7 @@ jobs:
         run: |
           sed -i 's/version\ =\ "[0-9]\+\.[0-9]\+\.[0-9]\+"/version\ =\ "${{ github.event.inputs.versionName }}"/g' pyproject.toml
           git add pyproject.toml
-          git commit -S --message "Prepare release ${{ github.event.inputs.versionName }}"
+          git commit -S --allow-empty --message "Prepare release ${{ github.event.inputs.versionName }}"
           echo "commit=$(git rev-parse HEAD)" >> "$GITHUB_OUTPUT"
           git push origin release/${{ github.event.inputs.versionName }}